Below are all the designs of the Gems' gemstones at various points in the Steven Universe franchise.
Unfused Gemstones
Rose Quartz
Hologram palette in "Rose's Scabbard"
Hologram palette in "Sworn to the Sword"
Hologram palette in "Chille Tid"
Earth palette in "The Answer"
Cloudy palette while the room is stormy in "Rose's Room"
Flashback palette in "Your Mother and Mine"
Earth palette in "Now We're Only Falling Apart"
Palette in Steven Universe: The Movie
Steven Universe
(Real) Rose Quartz
Pearl
Amethyst
Gem Warship Lighting Palette
Pink Diamond's Moon Base Palette
Pink Diamond's Zoo Palette
Garnet's Realm Palette
Sapphire
Night palette on Earth
Lapis Lazuli/"Mean" Lapis/"Nice" Lapis
"Nice" Lapis' gemstone day palette
Lapis' gemstone palette in Malachite's Realm
Lapis' gemstone palette when near Spinel's injector
Peridot/"Squaridot"
Gemstone Prime Kindergarten Control Room Screen palette
Gemstone palette in "Message Received"
Gemstone Beta Kindergarten palette
"Can't Go Back" palette
"Reunited" palette
Homeworld floor in the shadows palette
Bismuth
Inside Rose Quartz bubble
Gemstone Palette while in The Burning Room
Jasper
Steven Universe Future Opening Palette
Jasper's gemstone when shattered in "Fragments"
Yellow Pearl
Yellow Diamond
Diamond Communicator screen's color palette.
Blue Pearl
Blue Diamond
Retconned gemstone as seen in "The Answer"
Holly Blue Agate
Rutile Twins
Padparadscha
Pink Diamond
Jungle Moon Base palette
Pink Pearl
Ominous Shell Palette
White Diamond
Color palette in her ship
Spinel
Cherry Quartz
Blue Lace Agate
Nephrite ("Centi")
Heaven Beetle/Earth Beetle
Larimar
Biggs Jasper
Scrapped simplistic "Change Your Mind" design
Biggs Jasper's cracked gemstone in "Volleyball"
Orange Spodumene
Bixbite
Ocean Jasper
Tongue Monster
Snowflake Obsidian
Zebra Jasper
Zebra Jasper's cracked gemstone in "Volleyball"
Lace Amethyst
"Change Your Mind" design
Aquamarine
Topaz
Defending Zircon/Prosecuting Zircon
Emerald
Carnelian
The Famethyst
Chert
Flint
Aquamarines
Bismuths
Jades
Jaspers
Nephrites
Peridots
Sapphires
Comby
Pebbles
Albite
Desert Glass
Blue Chalcedony
Big Bird
Moonstone
White Topaz
Water Bear
Chrysocolla
Beta Kindergarten Monsters
Grossular Diopside/Titanite
Lonely Pearl
Hessonite
Demantoid
Pyrope
Electric Skulls
Soundtrack Attack Gems
Fusions
Garnet
Opal
Sugilite
Alexandrite
Malachite
Stevonnie/Steg
Rainbow Quartz/Rainbow Quartz 2.0
Sardonyx
Pearl's gem on Sardonyx in Sardonyx's Room (lights on)
Smoky Quartz
Amethyst's gemstone in "Sardonyx Tonight" (lights off)
Zebra Jasper
(Fusion) Topaz
Rhodonite
The color palette of Rhodonite's Pearl gemstone in the Homeworld Kindergarten, covered by a transparent shawl
The color palette of Rhodonite's Pearl gemstone in the Sun Incinerator, covered by a transparent shawl
The color palette of Rhodonite's Pearl gemstone in the Sun Incinerator during the power outage, covered by a transparent shawl
The color palette of Rhodonite's Pearl gemstone at night during the movie, covered by a transparent shawl
The color palette of Rhodonite's Pearl gemstone during Sadie's concert, covered by a transparent shawl
The color palette of Rhodonite's Pearl gemstone at night while inside Steven's shrinking bubble, covered by a transparent shawl
The color palette of Rhodonite's Pearl gemstone during Steven's nightmare party, covered by a transparent shawl
Fluorite
Fluorite's navel gem, day palette
Fluorite's navel gem, Sun Incinerator palette
Fluorite's navel gem, Sun Incinerator power outage palette
Fluorite's navel gem, Steven's Shrinking Bubble palette
Fluorite's navel gem, night palette
Fluorite's navel gem, Steven's Nightmare Party palette
Lemon Jade
Sunstone
Obsidian
Watermelon Tourmaline
Retconned design from "Beach Party" (Right Pupil)
Retconned design from "Beach Party" (Left Pupil)
Mega Pearl
Mega Pearl's Pearl Ominous Reef Palette
Crazy Lace Agate
Bluebird Azurite
Forced Fusions
Cluster Gems